Memory is widely used in various electronic devices such as cellular telephones, digital cameras, personal digital assistants, medical electronics, mobile computing devices, non-mobile computing devices and data servers. Memory may comprise non-volatile memory or volatile memory. A non-volatile memory allows information to be stored and retained even when the non-volatile memory is not connected to a source of power (e.g., a battery).
One example of a non-volatile memory is magnetoresistive random access memory (MRAM), which uses magnetization to represent stored data, in contrast to other memory technologies that use electronic charges to store data. Generally, MRAM includes a large number of magnetic memory cells formed on a semiconductor substrate, where each memory cell represents one data bit. A bit of data is written to a memory cell by changing the magnetization direction of a magnetic element within the memory cell, and a bit is read by measuring the resistance of the memory cell (low resistance typically represents a “0” bit and high resistance typically represents a “1” bit).
Although MRAM is a promising technology, previous MRAM memory cells were overly complicated to manufacture, operated inefficiently and/or did not switch deterministically.